Small size high efficiency wideband class-f amplifier based on harmonic stretching

Abstract

The application discloses a small-size high-efficiency wideband class-F amplifier based on harmonic stretching, and solves the problem that the existing class-F amplifier is difficult to realize second harmonic impedance short circuit and third harmonic impedance open circuit at the current source end face in a wideband range. DS , a power amplifier tube V GS , a first microstrip TL1, a second microstrip TL2, one end of the first microstrip TL1 and one end of the second microstrip TL2 being connected to a first node A, the other end of the second microstrip TL2 being connected to a second node B, the other end of the first microstrip TL1 and the drain of the power amplifier tube V GS being connected to a third node C; the power supply V DS is connected to the second node B; and the first microstrip TL1 and / or the second microstrip TL2 is a variable cross-section microstrip.

Description

Technical Field

[0001] This invention relates to power amplifiers, and more particularly to a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching. Background Technology

[0002] In recent years, research on high-efficiency broadband power amplifiers has received widespread attention because their use can effectively reduce base station power consumption, thereby lowering base station operating costs. Meanwhile, the increasing demands for signal bandwidth in the 5G era have made the development of a high-efficiency broadband power amplifier a focal point in the industry.

[0003] In theory, a Class F amplifier can achieve 100% efficiency by having non-overlapping square wave voltage signals and half-sine wave current signals at the power amplifier tube current source. However, this requires controlling an infinite number of harmonic impedances. This increases the complexity of the circuit implementation and results in a huge board area, which is not conducive to the miniaturization design of base stations.

[0004] Figure 1 This is a schematic diagram of the existing Class F amplifier architecture. In practice, Class F amplifiers only control the 2nd and 3rd harmonic impedances to improve efficiency. However, traditional harmonic impedance design methods significantly reduce the operating bandwidth, severely hindering the application of Class F amplifiers in broadband scenarios. Class F amplifiers require short-circuiting the 2nd harmonic impedance and opening the 3rd harmonic impedance at node C (the current source end face of the power amplifier tube), while simultaneously matching the fundamental impedance to a suitable load Zo, thereby achieving high efficiency. Figure 1 TL4 is a microstrip with a conventional structure. It can achieve a short-circuit effect on the third harmonic impedance under broadband conditions at node A. However, after passing through TL1, the open-circuit effect at node C (the current source end face of the power amplifier tube) deteriorates sharply with increasing bandwidth. Similarly, Figure 1 TL5 is a microstrip with a common structure. It can achieve the short-circuit effect of second harmonic impedance under broadband conditions at node B. However, after passing through TL2 and TL1, the short-circuit effect at node C (the current source end face of the power amplifier tube) deteriorates sharply with the increase of bandwidth.

[0005] in addition, Figure 1 The microstrip lines along the main transmission paths are all made using standard transmission lines. The use of standard transmission lines makes it difficult for the fundamental impedance, second harmonic impedance, and third harmonic impedance to simultaneously meet the impedance requirements of a Class F amplifier, and some deviations will occur.

[0006] Therefore, in practical applications, only a few harmonics are controlled, resulting in efficiency below 100%. Furthermore, due to the complexity of the circuitry, harmonic control can only be achieved at specific frequencies after passing through the transmission line, which limits broadband applications. While some architectures can provide wider bandwidth for Class F, the use of repetitive transmission line architectures inevitably requires a large circuit area. Summary of the Invention

[0007] The purpose of this invention is to provide a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, which solves the technical problem that existing Class F amplifiers are difficult to achieve second harmonic impedance short circuit and third harmonic impedance open circuit at the current source end face in the broadband range.

[0008] To achieve the above objectives, the present invention employs the following four technical solutions:

[0009] The first type of small-size, high-efficiency broadband Class F amplifier based on harmonic stretching includes a power supply V DS Power amplifier tube V GS A first microstrip TL1 and a second microstrip TL2 are connected. One end of the first microstrip TL1 and one end of the second microstrip TL2 are connected to a first node A, and the other end of the second microstrip TL2 is connected to a second node B. The other end of the first microstrip TL1 is connected to the power amplifier tube V. GS The drain is connected to the third node C;

[0010] Its special feature is:

[0011] The power supply V DS Connected to the second node B;

[0012] The first microstrip TL1 and / or the second microstrip TL2 are variable cross-section microstrips.

[0013] Furthermore, the first microstrip TL1 and the second microstrip TL2 adopt one of the following variable cross-section methods:

[0014] 1) At least two transmission lines of unequal length are connected in parallel;

[0015] 2) At least two transmission lines of unequal length are coupled;

[0016] 3) One of the end faces is a zigzag or oblique microstrip line;

[0017] 4) Both end faces are zigzag or oblique line microstrip lines;

[0018] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0019] The second type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS The system comprises a first microstrip TL1, a second microstrip TL2, and a fifth microstrip TL5. One end of the first microstrip TL1 and one end of the second microstrip TL2 are connected to a first node A. The other end of the second microstrip TL2 and one end of the fifth microstrip TL5 are connected to a second node B. The other end of the first microstrip TL1 is connected to the power amplifier transistor V. GSThe drain is connected to the third node C;

[0020] Its special feature is:

[0021] The power supply V DS Connected to the other end of the fifth microstrip TL5;

[0022] The first microstrip TL1, the second microstrip TL2 and / or the fifth microstrip TL5 are variable cross-section microstrips.

[0023] Furthermore, the first microstrip TL1, the second microstrip TL2, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0024] 1) At least two transmission lines of unequal length are connected in parallel;

[0025] 2) At least two transmission lines of unequal length are coupled;

[0026] 3) One of the end faces is a zigzag or oblique microstrip line;

[0027] 4) Both end faces are zigzag or oblique line microstrip lines;

[0028] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0029] The third type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS The system comprises a first microstrip TL1, a second microstrip TL2, a fourth microstrip TL4, and a fifth microstrip TL5. One end of the first microstrip TL1, one end of the fourth microstrip TL4, and one end of the second microstrip TL2 are connected to a first node A. The other end of the second microstrip TL2 and one end of the fifth microstrip TL5 are connected to a second node B. The other end of the first microstrip TL1 and the power amplifier tube V are also connected. GS The drain is connected to the third node C;

[0030] Its special feature is:

[0031] The power supply V DS Connected to the other end of the fourth microstrip TL4;

[0032] The first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4 and / or the fifth microstrip TL5 are variable cross-section microstrips.

[0033] Furthermore, the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0034] 1) At least two transmission lines of unequal length are connected in parallel;

[0035] 2) At least two transmission lines of unequal length are coupled;

[0036] 3) One of the end faces is a zigzag or oblique microstrip line;

[0037] 4) Both end faces are zigzag or oblique line microstrip lines;

[0038] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0039] The fourth type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS The system comprises a first microstrip TL1, a second microstrip TL2, a third microstrip TL3, a fourth microstrip TL4, and a fifth microstrip TL5. One end of the first microstrip TL1, one end of the fourth microstrip TL4, and one end of the second microstrip TL2 are connected to a first node A. The other end of the second microstrip TL2 and one end of the fifth microstrip TL5 are connected to a second node B. The other end of the first microstrip TL1, one end of the third microstrip TL3, and the power amplifier transistor V are also connected. GS The drain is connected to the third node C;

[0040] Its special feature is:

[0041] The power supply V DS Connected to the other end of the third microstrip TL3;

[0042] The first microstrip TL1, the second microstrip TL2, the third microstrip TL3, the fourth microstrip TL4 and / or the fifth microstrip TL5 are variable cross-section microstrips.

[0043] Furthermore, the first microstrip TL1, the second microstrip TL2, the third microstrip TL3, the fourth microstrip TL4, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0044] 1) At least two transmission lines of unequal length are connected in parallel;

[0045] 2) At least two transmission lines of unequal length are coupled;

[0046] 3) One of the end faces is a zigzag or oblique microstrip line;

[0047] 4) Both end faces are zigzag or oblique line microstrip lines;

[0048] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0049] Furthermore, one end face of the first microstrip TL1 is a polygonal or oblique shape, and the polygonal or oblique end face is connected to the first node A;

[0050] One end face of the second microstrip TL2 is a polygonal or oblique shape, and the polygonal or oblique end face is connected to the second node B.

[0051] Furthermore, the opposite end faces of any adjacent microstrips are complementary structures.

[0052] Furthermore, the variable cross-section microstrip adopts PCB routing technology and is formed by stacking multiple microstrips with a constant length variation.

[0053] The beneficial effects of this invention are:

[0054] 1. Existing output matching networks require a huge board area when designing broadband Class F amplifiers. This invention uses harmonic stubs to extend bandwidth. Specifically, this invention uses a stretchable harmonic tuning circuit to extend the bandwidth of a small broadband RF amplifier, which is beneficial for miniaturized base station design. Simultaneously, by improving the structure of TL2 and TL1 between point C and point B, the bandwidth of the small broadband RF amplifier can be extended without changing the amplifier's inherent impedance. This avoids the application limitations of Class F amplifiers in broadband scenarios, effectively achieving short-circuiting of the second harmonic impedance and open-circuiting of the third harmonic impedance, allowing the fundamental impedance to be matched to a suitable load Zo, thereby achieving high efficiency.

[0055] 2. This invention can maintain the compactness of the matching network of the Class F amplifier.

[0056] 3. This invention utilizes the concept of the finite element method to superimpose microstrips of successively increasing or decreasing length, fabricated using multiple PCB trace processes, to approximate a zigzag or oblique microstrip line. Therefore, this variable cross-section microstrip and the corresponding Class F amplifier have the advantages of simple manufacturing process and reliable use. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of an existing Class F amplifier;

[0058] Figure 2 This is one of the structural schematic diagrams of a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching provided by the present invention;

[0059] Figure 3 This is the second schematic diagram of the structure of the small-size, high-efficiency broadband Class F amplifier based on harmonic stretching provided by the present invention;

[0060] Figure 4 This is the third schematic diagram of the structure of the small-size, high-efficiency broadband Class F amplifier based on harmonic stretching provided by the present invention;

[0061] Figure 5This is a schematic diagram of the structure of various microstrip lines in the Class F amplifier of the present invention, wherein a and b are microstrip lines with one end being a broken line shape, c is a microstrip line with both ends being oblique lines shape, and d is a microstrip line with both ends being broken lines shape;

[0062] Figure 6 In this embodiment of the invention, a slanted microstrip line is formed by stacking multiple microstrips with a constant length using PCB routing technology.

[0063] Figure 7 In this embodiment of the invention, a zigzag-shaped microstrip line is formed by stacking multiple microstrips with a constant length using PCB routing technology.

[0064] Figure 8 This is a comparison chart of simulation results between the Class F amplifier of this invention and existing Class F amplifiers. Detailed Implementation

[0065] This invention provides four types of small-size, high-efficiency, broadband Class F amplifiers based on harmonic stretching. These four types of small-size, high-efficiency, broadband Class F amplifiers based on harmonic stretching will be described below:

[0066] The first type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS A first microstrip TL1 and a second microstrip TL2 are connected. One end of the first microstrip TL1 and one end of the second microstrip TL2 are connected to a first node A, and the other end of the second microstrip TL2 is connected to a second node B. The other end of the first microstrip TL1 is connected to the power amplifier tube V. GS The drain is connected to the third node C; the power supply V DS Connected to the second node B; in this embodiment, the first microstrip TL1 and the second microstrip TL2 are variable cross-section microstrips. In other embodiments, either the first microstrip TL1 or the second microstrip TL2 can be a variable cross-section microstrip. Figure 5 As shown, the first microstrip TL1 and the second microstrip TL2 adopt one of the following variable cross-section methods:

[0067] 1) At least two transmission lines of unequal length are connected in parallel;

[0068] 2) At least two transmission lines of different lengths are coupled; it should be noted that coupling here simply means that two metal wires are soldered together, or that the two ends of two metal wires are connected by a capacitor to transmit signals.

[0069] 3) One of the end faces is a zigzag or oblique microstrip line, such as... Figure 5 As shown in (a) and (b);

[0070] 4) Microstrip lines with both end faces being either zigzag or oblique, such as... Figure 5 As shown in (c) and (d);

[0071] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0072] It is worth mentioning that in the first and the following three small-size, high-efficiency broadband Class F amplifiers based on harmonic stretching, the width (ε) of the first microstrip TL1 and the second microstrip TL2 eff ) and length (λ) wavelength The calculation formula for ) is as follows:

[0073]

[0074]

[0075] In the formula, h is the microstrip line height, W is the microstrip line width, λ0 is the wavelength of light, and ε r is the dielectric constant, and f is the frequency.

[0076] The second type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS The system consists of a first microstrip TL1, a second microstrip TL2, and a fifth microstrip TL5. One end of the first microstrip TL1 and one end of the second microstrip TL2 are connected to a first node A. The other end of the second microstrip TL2 and one end of the fifth microstrip TL5 are connected to a second node B. The other end of the first microstrip TL1 is connected to the power amplifier transistor V. GS The drain is connected to the third node C; the power supply V DS Connected to the other end of the fifth microstrip TL5; in this embodiment, the first microstrip TL1, the second microstrip TL2, and the fifth microstrip TL5 are all variable cross-section microstrips. In other embodiments, one or two of the first microstrip TL1, the second microstrip TL2, and the fifth microstrip TL5 may be variable cross-section microstrips. Figure 5 As shown, the first microstrip TL1, the second microstrip TL2, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0077] 1) At least two transmission lines of unequal length are connected in parallel;

[0078] 2) At least two transmission lines of unequal length are coupled;

[0079] 3) One of the end faces is a zigzag or oblique microstrip line, such as... Figure 5 As shown in (a) and (b);

[0080] 4) Microstrip lines with both end faces being either zigzag or oblique, such as... Figure 5 As shown in (c) and (d);

[0081] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0082] The third type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V. DS Power amplifier tube V GS The microstrip transistors are: TL1 (first microstrip), TL2 (second microstrip), TL4 (fourth microstrip), and TL5 (fifth microstrip). One end of TL1, TL4, and TL2 is connected to node A. The other end of TL2 and TL5 is connected to node B. The other end of TL1 and the power amplifier transistor V are also connected. GS The drain is connected to the third node C; the power supply V DS Connected to the other end of the fourth microstrip TL4; in this embodiment, the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 are all variable cross-section microstrips. In other embodiments, one, two, or three of the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 may be variable cross-section microstrips. Figure 5 As shown, the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0083] 1) At least two transmission lines of unequal length are connected in parallel;

[0084] 2) At least two transmission lines of unequal length are coupled;

[0085] 3) One of the end faces is a zigzag or oblique microstrip line, such as... Figure 5 As shown in (a) and (b);

[0086] 4) Microstrip lines with both end faces being either zigzag or oblique, such as... Figure 5 As shown in (c) and (d);

[0087] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0088] In this structure, the fourth microstrip TL4 achieves a short-circuit effect on the third harmonic impedance at the first node A under broadband conditions. After passing through the polygonal or oblique-shaped first microstrip TL1, the open-circuit effect at the third node C remains essentially unchanged with increasing bandwidth. The fifth microstrip TL5, also a polygonal or oblique-shaped microstrip, achieves a short-circuit effect on the second harmonic impedance at the second node B under broadband conditions. After passing through the trapezoidal first microstrip TL1 and the second microstrip TL2, the short-circuit effect at the third node C remains essentially unchanged with increasing bandwidth. The length of the transmission line or microstrip line is related to the carrier frequency and bandwidth; in specific applications, the length and width need to be designed for amplifiers with different carriers and bandwidths.

[0089] The fourth type is a small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, such as... Figure 2 or Figure 3 or Figure 4 As shown, it includes power supply V DS Power amplifier tube V GS Microstrip TL1, microstrip TL2, microstrip TL3, microstrip TL4, and microstrip TL5 are connected. One end of microstrip TL1, one end of microstrip TL4, and one end of microstrip TL2 are connected to the first node A. The other end of microstrip TL2 and one end of microstrip TL5 are connected to the second node B. The other end of microstrip TL1, one end of microstrip TL3, and the power amplifier tube V are also connected. GS The drain is connected to the third node C; the power supply V DS It is connected to the other end of the third microstrip TL3; in this embodiment, the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 are all variable cross-section microstrips. In other embodiments, one or more of the first microstrip TL1, the second microstrip TL2, the third microstrip TL3, the fourth microstrip TL4, and the fifth microstrip TL5 may be variable cross-section microstrips.

[0090] like Figure 5 As shown, the first microstrip TL1, the second microstrip TL2, the fourth microstrip TL4, and the fifth microstrip TL5 adopt one of the following variable cross-section methods:

[0091] 1) At least two transmission lines of unequal length are connected in parallel;

[0092] 2) At least two transmission lines of unequal length are coupled;

[0093] 3) One of the end faces is a zigzag or oblique microstrip line, such as... Figure 5 As shown in (a) and (b);

[0094] 4) Microstrip lines with both end faces being either zigzag or oblique, such as... Figure 5 As shown in (c) and (d);

[0095] 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width increases as it gets closer to the end.

[0096] When one end face of the first microstrip TL1 is a polygonal or oblique shape, the polygonal or oblique end face can be connected to the first node A; when one end face of the second microstrip TL2 is a polygonal or oblique shape, the polygonal or oblique end face can be connected to the second node B.

[0097] It should be noted that in this embodiment, if the following is adopted... Figure 5Arbitrary combinations of various inclined plane structures may still cause boundary effects in the system's transmitted signals, resulting in oscillations or poor filtering (narrowband). Therefore, it is best to design a geometrically related pairing of microstrips. For example, if the inclined plane of the preceding microstrip is a concave structure, then the following microstrip should ideally adopt a matching convex structure, like the fit between a key and a lock, to minimize boundary effects. Furthermore, because the microstrips of this invention use... Figure 5 The inclined plane combination shown can easily correct frequency shift on the main transmission path, so it can take into account the fundamental frequency and various harmonics or higher frequency harmonic impedances. In particular, it can meet the impedance requirements of the fundamental frequency impedance, second harmonic impedance and third harmonic impedance at the same time as the Class F amplifier.

[0098] like Figure 2 As shown, when the variable cross-section of the first microstrip TL1 and the second microstrip is an inclined line-shaped end face tilted to the lower right, then the end of the second microstrip TL2 opposite to the variable cross-section of the first microstrip TL1 is an inclined line-shaped end face tilted to the upper left; as shown Figure 3 As shown, when the variable cross-section of the first microstrip TL1 and the second microstrip TL2 is a concave polygonal end face in the direction away from the second microstrip TL2, then the end of the second microstrip TL2 opposite to the variable cross-section of the first microstrip TL1 is a polygonal end face convex in the direction closer to the first microstrip TL1; as Figure 4 As shown, when both ends of the first microstrip TL1 adopt a slanted end face that slopes to the lower right, both ends of the second microstrip TL2 adopt a slanted end face that slopes to the upper left. This avoids boundary effects and can easily correct frequency shift phenomena on the main transmission path, thus taking into account the impedance of the fundamental frequency and various harmonics or higher frequency harmonics.

[0099] In addition, such as Figure 6 and Figure 7 As shown, both zigzag and oblique microstrip lines can be constructed using PCB routing technology by stacking multiple microstrips with a constant length variation.

[0100] like Figure 8As shown, the simulation results of the fourth type of small-size, high-efficiency broadband Class-F amplifier based on harmonic stretching are presented. The circular curve represents the simulation results of existing Class-F amplifiers. The results show a gain spike between 4.5-5 GHz, which affects signal transmission, causing the calculated bandwidth BW0 or BW1 to be smaller than the bandwidth BW2. Therefore, in the small-size, high-efficiency broadband Class-F amplifier based on harmonic stretching provided in this embodiment, various microstrip line structures will not exhibit oscillation or resonance phenomena. Furthermore, using the small-size, high-efficiency broadband Class-F amplifier based on harmonic stretching provided in this embodiment, the 2nd and 3rd harmonic impedances can achieve open-circuit and short-circuit effects over a wider bandwidth (fundamental frequency of 1.9 GHz).

Claims

1. A small-size, high-efficiency broadband Class F amplifier based on harmonic stretching, including a power supply V DS Power amplifier tube V GS The microstrip transistors are: TL1 (first microstrip), TL2 (second microstrip), TL3 (third microstrip), TL4 (fourth microstrip), and TL5 (fifth microstrip). One end of TL1, TL4, and TL2 is connected to a first node A. The other end of TL2 and TL5 is connected to a second node B. The other end of TL1, TL3, and V are connected to the power amplifier transistor V. GS The drain is connected to the third node C; Its features are: The power supply V DS Connected to the other end of the third microstrip TL3; The first microstrip TL1, the second microstrip TL2, the third microstrip TL3, the fourth microstrip TL4 and the fifth microstrip TL5 are variable cross-section microstrips, and the opposite end faces of any adjacent microstrips are complementary structures; the variable cross-section microstrips are constructed using PCB trace technology and are made by stacking multiple microstrips with a constant length variation.

2. The small-size, high-efficiency broadband Class F amplifier based on harmonic stretching according to claim 1, characterized in that, The first microstrip TL1, the second microstrip TL2, the third microstrip TL3, the fourth microstrip TL4, and the fifth microstrip TL5 adopt one of the following variable cross-section methods: 1) At least two transmission lines of unequal length are connected in parallel; 2) At least two transmission lines of unequal length are connected; 3) One of the end faces is a zigzag or oblique microstrip line; 4) Both end faces are zigzag or oblique line microstrip lines; 5) One or both ends of the microstrip have variable cross-sections, and the cross-section width is larger closer to the end.

3. The small-size, high-efficiency broadband Class F amplifier based on harmonic stretching according to claim 2, characterized in that, One end face of the first microstrip TL1 is a polygonal or oblique shape, and the polygonal or oblique end face is connected to the first node A; One end face of the second microstrip TL2 is a polygonal or oblique shape, and the polygonal or oblique end face is connected to the second node B.

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